code: def standardized_mean_squared_error(
      pred_dist: MultivariateNormal,
      test_y: torch.Tensor,
  ):
      """Standardized mean squared error.
  
      Standardizes the mean squared error by the variance of the test data.
      """
      return (
          mean_squared_error(pred_dist, test_y, squared=True)
          / test_y.var()
      )
  
file_path: gpytorch/gpytorch/metrics/metrics.py
imports: from math import pi
  from typing import Optional
  import torch
  from ..distributions import MultitaskMultivariateNormal, MultivariateNormal
label_desc: Use image node_id 3 for calling a global function with example usage: standardized_mean_squared_error(pred_dist, test_y) and returns: unknown